Volatile emissions from Deccan volcanic eruptions and their effects on climate across the K-Pg boundary

The Deccan Volcanic Province (DVP) hosts approximately one million km³ of basaltic lava, emplaced over a period of about one million years across the Cretaceous-Palaeogene (K-Pg) boundary associated with the major extinction event ~66 Ma ago. This review synthesises the current state of knowledge of DVP pre-eruptive magmatic volatile (H₂O, CO₂, S, Cl, F) contents gleaned from direct measurements of melt inclusions, trace element proxies, and equilibrium melt calculations. Most direct volatile measurements are from Western Ghats tholeiites, with limited data available for the minor picritic, alkaline, carbonatitic, and silicic lithologies across other DVP sub-provinces. Western Ghats eruption geochronology and palaeotemperature trends across the K-Pg boundary suggest that the peak in lava extrusion rate was decoupled from the phase of maximum volatile emissions. Resolving this temporal incongruence will require improved constraints on magma volatile contents; emission timelines and fluxes; the extent of stratospheric injection; and passive emissions from magmatic intrusions; as well as geochronological and volumetric data across different DVP formations and sub-provinces. Volatile emissions from DVP eruptions induced sustained climatic perturbations lasting ~1 Myr across the K-Pg boundary, in contrast to the temporally constrained abrupt changes triggered by the Chicxulub impact at the K-Pg boundary. We outline the outstanding challenges in deploying geochemical approaches to obtain DVP magma volatile contents, and offer potential future directions to estimate the climatic impact of DVP eruptions.